Babble

Babble is an alpha-stage macOS dictation app focused on local, realtime speech transcription.

The app currently targets push-to-talk style dictation, realtime text insertion, custom vocabulary support, local VAD, and local punctuation/segmentation for supported models. It should be treated as an experimental developer build rather than a finished product.

The key feature here is realtime output to target text input areas, NOT output AFTER transcription, or to a mid buffer target w/ copy/paste to final target.

Status

Babble is in alpha.

Expect rough edges, model changes, and occasional setup churn. The current repository is most useful for contributors or testers who are comfortable building a macOS app from source.

Features

• Local realtime dictation on macOS
• Voxtral realtime transcription through MLX
• Nemotron 3.5 ASR streaming through a forked speech-swift/CoreML runtime
• Local Silero VAD for speech boundary handling
• Local CoreML punctuation and sentence segmentation for Nemotron output
• Custom vocabulary support for Nemotron word boosting
• Menu bar app, recording HUD, history, and settings UI

Requirements

• macOS 15 or newer
• Xcode with the macOS toolchain installed
• Swift Package Manager
• A local checkout of soloish90/speech-swift on the word-boosting branch next to this repository:

repos/
  babble/
  speech-swift/

Babble uses a local Swift package dependency at ../speech-swift. For now, that checkout must be the Babble-compatible fork/branch:

git clone https://github.com/soloish90/speech-swift.git
cd speech-swift
git checkout word-boosting

Build

From the repository root:

./build-macos.sh --config debug --install

This builds the app with Xcode, signs it with an available Apple Development identity or ad-hoc signing, and installs it to:

/Applications/Babble.app

To build without installing:

./build-macos.sh --config debug --no-install

You can use --config release for a release build.

Run

After installing:

./run-macos.sh

The run script launches the installed app. If the app is not installed yet, run the build command above first.

Models

Babble manages supported local model downloads from the app's Models settings screen. Model files are stored under the app's Application Support models directory.

Current local realtime model paths include:

• Voxtral Mini 4B Realtime
• Nemotron 3.5 ASR Streaming

Nemotron also uses companion assets for word boosting, VAD, and punctuation. The app's model installer is responsible for keeping those assets together.

Tests

Run the Swift test suite with:

swift test

Some tests require local model assets or optional environment variables and may skip when those assets are not present.

Repository Layout

• Sources/BabbleMac/ - macOS app, settings, sessions, and UI code
• Sources/BabbleCore/ - shared app logic
• Sources/VoxtralEngine/ - Voxtral realtime engine integration
• Sources/PunctuationEngine/ - local punctuation model runtime
• Tests/ - Swift test targets
• docs/ - development notes and migration plans
• tools/ - developer utilities
• macOS/scripts/ - macOS build and packaging scripts

The supported repo-root entrypoints are:

• ./build-macos.sh
• ./run-macos.sh

Notes

Babble is under active development. Public APIs, model choices, and setup details may change while the app moves toward a more stable release.